Common Species of Pests in Food

Pests found in food covers a large variety of insects, including beetles and moths.

Learn more below about common species of Stored Product Insects (SPIs) found in Barbados.

Almond Moth

(Cadra cautella)

The Almond Moth goes by the nicknames “Cocoa Moth” and “Tropical Warehouse Moth”. The almond moth infests stored products and the adults can fly.

A sign of infestation in the product is contamination with silk webbing, frass, cast skins, pupal cases and adult remains.

Appearance

The body is 7.5 – 10 mm long.

The adult almond moth has a wing span of 19 mm.

The forewings are grey to dusty brown.

The larva is white to pink in colour and has a distinctive brown head

There is a dark straight band across the forewing, which is paler on the inner edge.

Lifecycle

The female lays 150 - 200 eggs loosely and randomly on a food source.

The larva can grow to 12.7 mm in length.

When the larva is mature, it will actively leave the food source and search for a site in which to pupate.

The larva pupates in a silk cocoon.

Habits

The almond moth is found worldwide in processing facilities, warehouses and households.

It feeds on grain, cereal products, oilseeds and dried plant products, like nuts, fruit and tobacco.

The larva burrows into food and creates silk tunnels in which it will be concealed while feeding.

Large larva can burrow through packing

Australian Spider Beetle

(Ptinus Tectus)

Appearance

Covered in brown and golden hairs, the Australian spider beetle has a spider-like appearance and adults grow to an approximate 2.4 – 4mm in length.

Lifecycle

Australian spider beetles live for up to 3 – 4 months at 20 - 25°C.

Feeding Habits

Larvae are often found feeding on miscellaneous debris, and the Australia spider beetle possesses the ability to bore into various inedible materials prior to pupation. Active in dark, damp places, the Australian spider beetle is often associated with bird nests.

Bean Weevil

(Acanthoscelides obtectus)

Appearance

2.0 – 3.0mm long, mottled brown in colour.

They have a ‘tear drop’ like body shape and are covered in short hairs.

Saw-tooth like antennae and elytra that do not cover the entire abdomen.

Lifecycle

Lifecycle usually lasts 2-4 months.

The larvae feed within the beans as they mature.

The larval stage can take from a few weeks to many months to complete, depending upon temperature and moisture of the bean. Pupation is within the bean. Circular holes are cut for the adult to emerge.

Development and breeding goes on as long as there is any food left in the bean and the temperature is right (warmer temperatures are preferred).

Habits

Larvae feed mostly inside beans.

These weevils attack all legumes, including kidney beans, green beans, peas and lentils.

Lifecycle

Habits

Liposcelis bostrychophila — Common in homes.

Lepinotus patruelis — Common in factories and on pallets.

Broadhorned Flour Beetle

(Gnatocerus Cornutus)

Appearance

An approximate 3.5 – 4.5mm in length, male broadhorned beetles have two enlarged mandibles on the head, giving the appearance of horns and thus their name. Females are very similar In appearance to the confused flour beetle.

Feeding Habits

Cheese Mites

Appearance

Cheese mites have soft, hairy cream white bodies with 8 hairless legs and adults grow up to an approximate 0.5mm in length.

Lifecycle

The cheese mite favours warm, moist conditions and eggs mature in 10 days at room temperatures. Females can lay up to 900 eggs in a lifetime at a rate of 20 – 30 a day. Adult cheese mites can live for up to 60 – 70 days.

Feeding habits

With a preference for old cheese to young cheese, these mites also feed on nuts, dried eggs, fruit, flour and tobacco. Cheese mites are capable of contaminating foods to cause skin or gut irritation.

Cigarette Beetle

(Lasioderma serricorne)

The Cigarette beetle is a very common commercial pest.

Appearance

The Cigarette Beetle is about 2-4mm in length.

The adult is whitish in color, with the head dark brown to tan, and are densely haired.

The cigarette beetle closely resembles the drugstore beetle.

The cigarette beetle has the head bent down nearly at right angles to the body giving it a humped back appearance when viewed from the side.

The larvae are about 4 mm long and somewhat bent.

Lifecycle

The adult beetles live from 2 to 4 weeks and during this time the females may deposit between 10-100 eggs.

The eggs are laid loosely on the infested material.

The larval period usually ranges from four to five months, but under very favorable conditions the development from egg to adult may occur in 6 to 8 weeks.

When the larvae are fully grown, pupation occurs and they remain in this resting stage for 12 to 18 days.

Habits

They cannot feed on whole grain, but can feed on broken kernels that are usually present.

Copra beetle/Red Legged Ham Beetle

(Necrobia Rufipes)

Appearance

Adults: 3/16" in length.

The upper surfaces of the body are a shiny metallic bluish-green. The underside of the abdomen is dark blue. Their legs are bright reddish-brown or orange. The antennae are reddish–brown with a dark brown or black club at the tip.

Lifecycle

Females lay up to 30 eggs per day in cracks or crevices of cured fish. The eggs take between four and six days to hatch.

The larvae will grow for 30 to 140 days, become less active and look for a dark place to pupate.

The pupal stage varies between 6 and 21 days.

An adult will mate soon after emerging from its pupal stage and can live for up to 14 months.

Habits

The adults fly and can therefore easily disperse to new sources of food.

They are destructive in both the larval and adult stages, although the larval stage is the most destructive.

They are also cannibalistic, preying on their own eggs and pupae.

Dermestes Beetle

(Dermestes beetle)

Appearance

Adult – 1/4"–3/8" in length. Black with a whitish band across the fore–part of the elytra.

Lifecycle

2–3 months at 18–25°C.

Habits

Feeds on various animal products including cheese.

Drug Store Beetle

(Stegobium Paniceum)

The drugstore beetle (also known as the Biscuit Beetle) gained its name because it was frequently found feeding on drugs in pharmacies many years ago. Now, they are customarily found infesting all types of dry stored food products, spices, seeds, grains and dried plant material.

Appearance

Approx. 3 - 4 mm long, red-brown, oval beetles.

The larvae are small and white approximately 0.5 mm long.

The drugstore beetle is a red-brown oval-shaped beetle.

Lifecycle

The adult beetles live from 2 to 4 weeks and during this time the females may deposit between 20-100 eggs.

The hatching larvae are 0.5 mm long and very mobile.

The larval period usually ranges from four to five months, but under favorable conditions the development from egg to adult may occur in 6 to 8 weeks.

When the larvae are fully grown, pupation occurs and they remain in this resting stage for 12 to 18 days.

Habits

It is not a major pest in stored grains but will attack spices, seeds, grains and dried plant material as well as packaging materials such as paper and cardboard.

They have also been known to feed on leather, wool, hair and books.

Their presence can be detected from pinhead holes in the infested items.

Packaging materials such as paper and cardboard are also attacked.

Since the drugstore beetle can fly well, the source of infestation can sometimes be hard to find.

The drugstore beetle is not a major pest in stored grains.

Flat Grain Beetle

(Cryptolestes Ferrugineus)

Appearance

Adult — About 1/8" in length. Flattened body with very long antennae. Light red to dark reddish brown.

Flour Mite/Grain Mite

Appearance

Lifecycle

9–11 days at 23°C and 90% relative humidity.

Habits

Under adverse conditions, may pass through a long and very resistant stage called a hypopus.

Foreign Grain Beetle

(Ahasverus adena)

It is frequently associated with hot spots in farm-stored grain. Although primarily a fungivorous species. The presence of this insect in farm-stored grain is taken as a warning that the grain is beginning to spoil and become moldy.

Appearance

The adult Foreign Grain Beetle is light brown and is about 2 mm long.

They are similar in appearance to the saw-tooth grain beetle, but they lack the tooth-like projections and are somewhat broader.

Larvae are initially white and gradually darken as they mature. They rarely grow larger than 3 mm and have no forked process at the tip of the abdomen.

Lifecycle

Adult females begin laying eggs around 3 - 4 days after emerging.

Mated males and females have an average lifespan of 159 and 208 days, respectively.

Eggs, which are laid singly or in clusters of two or three, hatch in 4 - 5 days.

Larval development is completed in 11 - 19 days. When ready to pupate, the larva constructs a chamber of food particles cemented together.

Pupation occurs after a prepupal period of 1 - 2 days, and adults emerge 3 - 5 days later.

Habits

The adults are long lived, fly well and run very rapidly.

This species occurs on a wide variety of foodstuffs, including grains, cereal products, oilseeds and their products, dried fruit, and spices.

It is a scavenger that feeds on molds, dead insects, and damaged foods.

On cereal grains, the embryo is a suitable food material. However, when found in large numbers they are probably feeding on molds present in the food.

Fur Beetle

(Attagenus pellio)

Appearance

Adult — 3/16"–1/4" long. Elongate oval. One small patch of white on each wing case, otherwise red–brown to black.

Larva — 1/4" long. Long orange tufts of hair on the last abdominal segment.

Larvae have a banded appearance.

Pupa — formed in the last larval skin.

Lifecycle

Mating takes place outdoors after which they fly indoors to lay eggs. Normally one generation per year but development may extend to three years.

Habits

A common inhabitant of birds nests. Adults feed outdoors often on Spiraea plants.

Grain Borer

Appearance

Antennae have 3 large segments at the end forming visible antenna clubs, reddish in colour.

The humped thorax covers the head, its front rim has teeth–like indentations.

Elytra (wing covers) are heavily punctated and drop off sharply at the back, giving the impression of a square end when seen from above.

Lifecycle

The female lays an average of 10 eggs on a grain of maize and the hatched larvae bore into the grain.

The larva undergoes up to 4 development phases and pupates inside the corn grain.

Lifecycles can be quite short, in good conditions (25 days at 34 °C, 75% relative humidity) there are several generations per year.

Habits

Adult beetle is a pest of stored maize, but also infests other types of grain. Larva bores tubular passages into the grain, typically making one main tunnel with smaller ones branching off.

Brought in from tropical Central America in cassava roots and tapioca products, as well as in starchy fruits and tubers.

Granary Weevil

(Sitophilus Granarius)

The Granary Weevil is among the most destructive of all stored grain insects. The larvae develop inside kernels of whole grain in storage. This makes an infestation difficult to remove in the milling process.

Appearance

Dark brown-black in colour.

It is about 2.5 - 5 mm in length.

They possess a long slender snout and cannot fly.

In the larval stage the weevils are legless, humpbacked, white to creamy white, with a small, tan head.

Weevils in the pupa stage have snouts like the adults.

Lifecycle

The egg, larva, and pupa stages of these weevils occur in the grain kernels and are rarely seen.

Emergence holes of the granary weevil are fairly large and tend to be more ragged than smooth and round.

Females drill a tiny hole in the grain kernel, deposit an egg in the cavity, then plug the hole with a gelatinous secretion.

The life cycle is about 30 to 40 days during the summer, and 123 to 148 days during the winter, depending on temperature.

Khapra Beetle

(Trogoderma granarium

The Khapra Beetle is considered to be the world's most destructive pest of stored grain and grain products. If left uncontrolled, this beetle can cover the surface of stored grain making it appear alive with crawling larvae

Appearance

The male is about 2 mm in length and the female is slightly larger (up to 3 mm).

Dark-brown beetle with yellow-brown to red-brown markings on the wing covers.

They are also covered with fine hairs which may trap dust, giving a dirty appearance.

The larvae are yellow to golden brown and reach a length of up to 5 mm. They are covered with thick, red-brown hairs with two tufts at the end of the abdomen.

Lifecycle

Adults are short-lived, completing their adult life in one to two weeks.

Mating occurs almost immediately after adult emergence, with oviposition for one to six days following.

In ideal conditions the life cycle can be completed in as few as 30 days.

Lesser Mealworm

Appearance

Larvae - 5/16" long. Slender, segmented and worm-like with three pairs of tiny legs on the thorax and one abdominal proleg at the rear.

Lifecycle

Females can lay up to at least 110 eggs a month and eggs hatch in 4-7 days. Larval development takes up to 7 weeks. Mature larvae seek a sheltered place to pupate for between 7 and 11 days.

An adult beetle may live up to two years.

Habits

The beetles are attracted to poultry operations, which have ideal conditions for their development. The damage to insulation is carried out by lesser mealworms seeking a safe place to pupate because the darkling beetles prey on the lesser mealworms.

Maize Weevil

(Sitophilus zaemais)

Also known as the Greater Rice Weevil. Maize Weevils are frequently regarded as primary pests of grain since they are able to infest otherwise undamaged grain.

They have also been seen to infest buckwheat, peas, acorns, chestnuts and cottonseed.

Appearance

It is about 2.5 - 4 mm long.

The head has a long slender snout.

Resembles rice weevil, only bigger and the red-brown spots on wing covers are more clearly marked.

It is a stronger flier than the rice weevil.

Lifecycle

The egg, larva, and pupa stages of these weevils occur in the grain kernels and are rarely seen.

Females drill a tiny hole in the grain kernel, deposit an egg in the cavity, then plug the hole with a gelatinous secretion.

The egg hatches into a young larva which bores toward the center of the kernel, feeds, grows, and pupates there.

New adults bore emergence holes from the inside, then leave to mate and begin a new generation.

Habits

Both larvae and adults will feed upon grain.

Weevil-damaged grain can be readily recognised by the presence of large holes which are the exit holes of the emerging adults.

Merchant Grain Beetle

(Oryzaephilus Mercator)

Merchant grain beetles are found in pantries or in food processing [link:/food-processing/] areas or warehouses.

Appearance

The adult beetle is dark brown.

Length is approximately 2.5mm to 3mm.

It has a slender, flattened body.

The adult can fly (although it rarely does).

Lifecycle

The females lays about 300 eggs in her lifetime.

Eggs are dropped loosely among grain kernels or tucked into a crevice in a kernel.

The tiny eggs are slender and white, and hatch in three to five days when environmental conditions are optimal .

The larvae emerge and crawl freely about the grain to feed on broken kernels. Larger larvae may tunnel into kernels to feed.

Total development from egg to adult requires about three to four weeks.

Habits

The Merchant Grain Beetle is a pest species found feeding in nuts, seeds, biscuits, dried fruit, grain and various other food products.

The beetles can chew through sealed packaging such as cardboard boxes, plastic bags and foil wrappings.

Mediterranean Flour Moth

(Ephestia kuhniella)

The Mediterranean flour moth larva is a very common commercial and pantry pest. It is a pest of mills and warehouses as it can clog machinery with its webs.

Appearance

Mediterranean Flour Moth adult has wingspread of about 20 – 22mm and when at rest it is 10 - 14 mm long.

The hind wings are dirty white while the forewings are blue-grey with transverse dark wavy bars and a row of dark spots at the tip.

The larvae are white in color with a brown head and neck shield.

The larvae can take on a pinkish or greenish hue and can reach a length of 15 - 20 mm.

The pupa form a brown, spindle shaped cocoon approximately 9 mm.

Lifecycle

The female lays between 100 - 700 eggs (usually 200) in and among the food source and usually fastens the eggs to the infested material.

The eggs usually hatch in 3 - 5 days and the hatching larvae produce a lot of webbing.

The young larvae confine themselves to silken tubes which are constantly spun.

The larva attains full size in around 40 days. The larva pupates in or on top of the infested material (usually flour) or in cracks and crevices nearby.

The life cycle can be completed in as few as 4 - 6 weeks but usually takes about 3 months.

Habits

The Mediterranean flour moth is mostly found infesting flour and meal.

It has also been found infesting grain, bran, cereal products, nuts, chocolate, seeds, beans, biscuits, dried fruits and other stored foods.

Rice Weevil

(Sitophilus Oryzae)

Rice weevils are pests of stored grain and seeds.

Appearance

The adult rice weevil is 2.5 - 3.5 mm long and has a slender, hard-shelled bodies that appear pitted or scarred with tiny holes.

They are brown-black in color and possess a long slender snout.

Rice weevils have four faint red-brown spots on the back of the abdomen.

Lifecycle

The adults live 3 to 6 months, infesting grain in the field.

The egg, larva, and pupa stages of these weevils occur in the grain kernels and are rarely seen.

Females drill a tiny hole in the grain kernel, deposit an egg in the cavity, then plug the hole with a gelatinous secretion.

The egg hatches into a young larva which bores toward the center of the kernel, feeds, grows, and pupates there.

New adults bore emergence holes from the inside, then leave to mate and begin a new generation.

Female rice weevils lay between 300 to 400 eggs, with the life cycle requiring about 32 days for completion. Two larvae can develop in one wheat kernel.

Habits

The adults can feign death by drawing up their legs close to the body, falling, and remaining silent when disturbed.

Emergence holes of the rice weevil are smaller than those of the granary weevil, and tend to be smooth and round.

There is generally no external evidence that the larvae have been eating and growing inside the seed until after about one month when the adult weevil chews through the seed coat and emerges.